1. Technical Field
This invention relates generally to a method and apparatus for directing a snow or debris blowing air blast under vehicles. More particularly, this invention relates to an apparatus and method for directing a low turbulence vehicle-mounted air blast for use in clearing snow or debris from a road or runway.
2. History of Related Art
Vehicle-mounted devices for use in clearing snow or debris from a road or runway typically include a front-mounted broom assembly and a rear-mounted air blast system as shown in FIG. 1. Alternatively, some prior art air blast systems are mounted between the front and rear axles. As the truck moves down the runway, the spinning broom on the front of the truck contacts the snow or debris on the runway and brushes the snow or debris both to the front and to one side. Then the snow or debris which has been swept to one side is blown farther across the runway by the air blast system.
As may be seen in FIG. 1, when it is desired to push the snow or debris to one side of the runway, specifically the left side as shown in the figure, the truck moves along the right side of the runway until it reaches the end. Upon reaching the end of the runway, the operator must re-configure the truck by repositioning the broom and redirecting the air blast. Note that in the truck moving up the runway on the right side of FIG. 1, the broom is positioned so that the near end is closest to the left or driver side of the truck going up the runway and the air blast is exiting the truck on the left side.
This switching of the direction of the air blast system and the changing of the angular orientation of the broom keeps the snow or debris moving from the right side of the runway to the left side of the runway. In one prior art configuration, the direction of the air blast at the rear end of the truck is controlled by the use of two multi-curved air ducts mounted on either side of the truck. These bends in the air ducts induce unwanted turbulence into the high velocity air flow. When it is desired to push the snow or debris to the right side of the truck, the air duct on the left side at the rear of the truck comes down and the air blast system causes high velocity air to pass from the left side to the right side of the truck to blow the snow or debris in the same direction that it is pushed by the broom.
Alternatively, some prior art air blast systems use an air duct with vanes to regulate the flow of air to the left or right depending on the direction that the broom is facing. The vanes are switched in order to change the direction of air flow from one side of the truck to the other. In this configuration, the air blast is split in two, with only half of the air flow going to the left or right.
When the truck comes to the end of the runway in prior art systems, the orientation of the broom and the direction of the air blast system are both reconfigured for another pass in the opposite direction down the runway. This reconfiguration of the truck for the second pass down the runway begins by first changing the direction of the air flow in the air blast system from one side to the other by repositioning the ducts or vanes. Following this repositioning, the broom in the front of the truck is repositioned. Thus, in prior art systems, the truck turnaround and reconfiguration time is a problem. Moreover, in the prior art configuration that utilizes vanes, the system is less efficient due to the reduction of air flow and decreased air speed.
While it is intended that the front mounted rotating broom remove most of the snow or debris from the runway and the air blast system both blow the loose snow or debris to one side and dry the surface of the runway, in actual practice it has been found that the broom does not remove all the snow from the surface of the runway. Moreover, in those prior art systems which have the air blast system at the rear of the truck, the snow remaining on the runway is compacted by the rear wheels of the truck before it is impacted by the high velocity air from the air blast system. Additionally, in those prior art systems with air ducts vanes, even if the system is mounted between the front and rear axles, the force of air flow is not powerful enough to remove all the snow from the surface of the runway.
What is needed is a vehicle-mounted air blast system which eliminates the need for reconfiguration of the air ducts whenever the vehicle turns around. Additionally, the air blast system should be positioned on the truck such that the blast of air moves the snow or debris from under the truck before it is compacted by the truck wheels. The air ducts of the air blast system should be designed to minimize air turbulence and allow the air ducts to be pulled up under the truck when not in use. Finally, the air blast system should be configured to create a powerful and efficient air flow which also operates as a vacuum to suction as much snow as possible from the surface of the runway.
The present invention is an apparatus and method for directing a low turbulence vehicle-mounted air blast for use in clearing snow or debris from a road or runway. The high velocity air passes through the air ducts into the channel which passes under the central portion of the truck. The air flow is not split in half, but is delivered in a single blast which powerfully blows the snow across the runway. Additionally, the passage of the high velocity air through the channel creates a vacuum which efficiently draws the snow and moisture off the runway surface and removes the snow from cracks in the runway. FIG. 5 illustrates the air duct on the left side of the truck engaging the channel passing under the central portion of the truck to provide an air blast exiting on the right side of the truck.
The turbulence of the air flow in the air blast system is minimized by the reduction in the amount and severity of the bends in the air ducts as compared to those used in prior art trucks. Additionally, internal baffles within the air ducts are used to further reduce the air flow turbulence. The air channel and air ducts are lowered toward the ground during operation. To eliminate the problem of the rear wheels compressing the snow on the runway, the air blast system has been moved to the central portion of the truck just behind the driver""s cab. As may be seen in FIG. 5, the air duct on the left side of the truck is positioned adjacent to an air channel which passes under the truck. This positioning of the air blast system in front of the rear wheels also enables a better weight distribution on the truck.
When the truck reaches the end of the runway, the air duct currently in use is lifted and the other air duct is lowered. In this way, the operation is without interruption and the blast of snow or debris is sent to the same side of the runway upon turnaround. When the air blast system is not in use and the truck is prepared for road travel, both the air ducts and the channel may be pulled up under the chassis of the truck as shown in FIG. 4 and FIG. 7.